ISO 32662-1:2025

Overview

ISO 32662-1:2025 - Liquid petroleum products - Determination of total contamination - Part 1: Middle distillates and diesel fuels - specifies a laboratory method to determine the content of undissolved substances (referred to as total contamination) in middle distillates and diesel fuels containing up to 30% FAME (fatty acid methyl esters). The method’s established working range is 12 mg/kg to 26 mg/kg. It is intended for products with kinematic viscosity not exceeding 8 mm2/s at 20 °C or 5 mm2/s at 40 °C; it can be applied outside these limits but with undetermined precision.

Key Topics and Requirements

• Principle: Weigh a test portion, filter under vacuum through a pre‑weighed glass‑fibre filter, wash, dry and re‑weigh the filter. Calculate contamination (mg/kg) from the mass difference.
• Working range and applicability: Validated between 12–26 mg/kg; applies to middle distillates and diesel fuels up to 30% FAME. Use for other fuels or higher viscosities is possible but precision is not established.
• Equipment & materials:
  • High‑retention glass fibre filters, 47 mm diameter, mean pore size 0.7 μm (e.g., GF‑F types have been found suitable, non‑endorsement).
  • Vacuum filtration apparatus capable of maintaining absolute pressure 2–5 kPa.
  • Oven (110 ±5 °C), desiccator, analytical balance (0.1 mg), wash bottle with heptane, etc.
• Sampling & cleaning: Follow ISO 3170 / ISO 3171 / EN 14275 for sampling. Strict cleaning of containers and apparatus is required to avoid contamination (detailed rinsing with detergent, propan‑2‑ol and heptane).
• Precision & reporting: Precision established via interlaboratory study using ISO 4259‑1. The standard specifies repeatability/reproducibility assessment and required test‑report information.
• Safety: The standard warns about hazardous materials and operations; users must establish appropriate safety and regulatory controls.

Applications and Users

• Who uses it: Fuel testing laboratories, refiners, distribution terminals, quality control teams, fuel certification bodies, and equipment manufacturers concerned with filterability and contamination control.
• Practical uses:
  • Routine quality control of diesel and middle distillates to prevent filter blockage and equipment damage.
  • Acceptance testing at storage, distribution and retail points.
  • Comparative and forensic analysis when contamination incidents affect engines or fuel systems.
  • Supporting compliance with fuel quality specifications (including paraffinic diesel per EN 15940).

Related Standards

• ISO 4259‑1 - precision assessment (interlaboratory study basis)
• ISO 3170 / ISO 3171 - sampling of hydrocarbon liquids
• EN 14275 - sampling from retail/commercial fuel dispensers
• EN 15940 - paraffinic diesel fuels
• Note: ISO 32662‑2 covers neat FAME testing methods.

Keywords: ISO 32662‑1:2025, total contamination, diesel fuels, middle distillates, FAME, kinematic viscosity, vacuum filtration, fuel quality testing.